scripts: BlueBoat: add leak failsafe

scripts/ardupilot/ArduRover/4.x/leak.lua

@@ -0,0 +1,45 @@
+-- Leak detection/failsafe functionality for the Navigator
+-- Intended for use with ArduRover (e.g. on a BlueBoat)
+
+---- USER CONFIG ----
+local warning_interval_ms = uint32_t(15000)  -- warn every 15s
+
+-- specify 1-2 failsafe modes for desired behaviour
+RoverMode = {
+    Hold = 4,
+    Loiter = 5,
+    RTL = 11,
+    SmartRTL = 12,
+}
+local failsafe_mode = {RoverMode.Loiter, RoverMode.Hold}  -- try to loiter, otherwise hold
+---------------------
+
+-- perform setup
+local navigator_leak_pin = 27
+gpio:pinMode(navigator_leak_pin,0)  -- configure as a digital input
+local warning_last_sent = uint32_t()
+
+-- define the loop
+function update()
+    if gpio:read(navigator_leak_pin) then
+        -- warn the operator, if they haven't been warned recently
+        if millis() - warning_last_sent > warning_interval_ms then
+            gcs:send_text(2, "Leak detected!")  -- critical level announcement
+            warning_last_sent = millis()
+        end
+        -- change mode, with an optional fallback
+        local current_mode = vehicle:get_mode()
+        if (
+          current_mode ~= failsafe_mode[1] and current_mode ~= failsafe_mode[2]  -- not already changed
+          and not vehicle:set_mode(failsafe_mode[1])  -- AND first change doesn't work
+          and failsafe_mode[2]  -- AND backup mode provided
+        ) then
+            vehicle:set_mode(failsafe_mode[2])
+        end
+    end
+
+    return update, 1000  -- check again after 1s
+end
+
+-- start the loop (immediately)
+return update()